(1) Field of the Invention
The present invention relates to an automatic repeater vaccinator apparatus for dispensing into an animal a predetermined volume of a fluid, in particular a fluid which is a vaccine, and reloading after each volume of fluid is dispensed. The apparatus comprises a handheld syringe for dispensing the fluid, a flexible conduit for transferring the fluid from a dispensing means to the syringe, and a reservoir for providing the fluid to the dispensing means. The dispensing means is electrically activated by a magnetically closeable switch (preferably a reed switch) in the syringe, which enables a predetermined volume of the fluid to be dispensed from the syringe when the dispensing means is activated and reloading fluid from the reservoir to replace the volume of fluid which has been dispensed from the syringe when the dispensing means is deactivated. Preferably, the dispensing means comprises a pump operated by a linear actuator such as a solenoid, which is electrically activated by the magnetically closeable switch in the syringe. The apparatus is particularly useful for inoculating poultry, particularly inoculating the poultry by the wing web method using the needle and hub assembly which comprises the filament to prevent leakage between inoculations.
(2) Description of Related Art
Vaccination of poultry has played an increasingly important role in the poultry industry, particularly since the advent of large-scale poultry operations which continuously raise poultry flocks one after an other without any down time between flocks to sanitize the facilities for raising the flocks. Because production of poultry is on such a large scale and the margin for profit on a per bird basis is so thin, there has been considerable interest in vaccination methods which reduce the time and cost of vaccinating poultry.
Traditionally, chicks are vaccinated by filling a handheld syringe with multiple doses of the vaccine, picking up a chick, and manually injecting the appropriate dose of vaccine into the chick. Because the entire vaccination process is manual and a large number of chicks must be vaccinated within a short period of time, the dose received by the chicks can be variable because of leakage of vaccine from the needle and miscalculation. To ensure that the chicks have received enough vaccine, the tendency is to over vaccinate the chicks, which increases the vaccine cost per chick. In addition, the handheld syringe holds only a limited number of doses which requires refilling the syringe multiple times throughout the vaccination process. Furthermore, because the distance the needle is inserted into the chick is determined by eye, for a number of chicks the needle will either be not inserted deep enough into the chick or will be inserted to deep which can kill the chick. To overcome the problems associated with manual vaccination methods, alternative vaccination methods have been developed.
Automatic egg vaccinators such as those disclosed in U.S. Pat. No. 5,158,038 to Sheeks et al., U.S. Pat. No. 5,056,464 to Lewis, U.S. Pat. No. Re. 35,973 and U.S. Pat. No. 5,136,979, both to Paul et al., U.S. Pat. No. 5,438,954 to Phelps et al., and U.S. Pat. No. 6,032,612 to Williams have been developed. While egg vaccinators are useful for some vaccine formulations such as Marek's disease vaccines, egg vaccinators are not useful for other vaccines such as Newcastle vaccines where maternal antibodies may negate the efficacy of the vaccine. Therefore, even though automatic egg vaccinators are available, the most common method for vaccinating poultry remains vaccinating new-born chicks or young chicks by hand.
Thus, a variety of methods for reducing the time and cost of vaccinating new-born chicks have been developed. For example, U.S. Pat. No. 5,468,227 to Haskell discloses an apparatus for wing-web vaccination of new-born or young chicks. To operate the apparatus, the operator places a chick in a trough in the apparatus, extends the chick's wing into a recess in the apparatus, and activates a power switch. The power switch simultaneously activates a solenoid which pushes a needle into the chick's wing web and activates a peristaltic pump which pumps vaccine from a reservoir to the needle and discharging therefrom into the wing web. As the pump shaft rotates, a pin wheel attached to a shaft connected to the pump contacts a micro-switch which breaks the circuit thereby terminating flow of the vaccine and causing retraction of the needle.
U.S. Pat. No. 3,964,481 to Gourlandt et al. discloses an apparatus for vaccinating animals including chicks. To operate the apparatus, the operator places the animal over an aperture in a retention plate of the apparatus and activates a switch which causes a needle afixed to a syringe driven by a piston operated by an electromagnet motor to extend a predetermined distance through the aperture and into the animal. When the needle has reached its predetermined distance, the piston further advances which causes a predetermined dose of vaccine to be dispensed into the animal and the electromagnet to be deactivated. A spring causes the piston to retract which during retraction creates a suction in the syringe which causes vaccine to be drawn into the syringe from a reservoir to replace the vaccine which had been dispensed.
U.S. Pat. No. 5,242,388 to Marshall, Sr. discloses an apparatus for operating a needle to inoculate the wing web of a bird. An arm rocks a needle holder back and forth between a serum container and web positioner, along a path which causes the needle holder to move substantially vertically into and out of the container and web positioner. Gears cause the needle holder to pivot on the arm in response to pivotal movement of the arm, so that the needle points downwardly throughout its movement.
While the above apparatuses have been useful, they are stationary devices which require the animal or chick to be placed into or held against the apparatus. It would be more convenient to have a handheld vaccinator but without the disadvantages of the traditional handheld syringe. To that end, U.S. Pat. No. 2,512,882 to Truesdale and U.S. Pat. No. 4,990,135 to Truesdale, Jr. disclose a repeater vaccinator for wing web inoculations comprising a syringe with a reservoir and a reciprocable needle having a portion movable into and out of the reservoir by action of a manually operated plunger. The needle has slots on either side or opening therethrough which are designed to positively attract and hold a predetermined dose of vaccine. In the rest position, the needle resides in the reservoir. When the syringe is placed against the wing web and the plunger is manually pressed, the needle exits the reservoir carrying with it the predetermined dose of vaccine and enters the wing web where the vaccine is deposited. Releasing the plunger causes the needle to retract back into the reservoir. The number doses contained within the vaccinator is limited by the size of the reservoir.
A back-fill repeater syringe which can be attached by a flexible conduit to a reservoir remote to the syringe is disclosed in U.S. Pat. No. 4,715,853 to Prindle. The syringe is manually operated by inserting the needle into an animal and pressing the head of the syringe against the animal which causes a plunger in the syringe to move forward to dispense a predetermined dose of vaccine in the syringe through the needle into the animal. Removing the needle from the animal causes the plunger to retract which draws vaccine from the reservoir to replace the dose of vaccine that had been dispensed.
While the handheld repeater syringes have been beneficial, they are manual in that they require constant hand motion to dispense the vaccine which causes operator fatigue and can lead to occupational diseases such as carpel tunnel syndrome. Therefore, there is a need for a handheld repeater syringe that does not require continual hand motion to dispense the vaccine.